Data on staph links gays

NEWS

by Bob Roehr

Gay men are significantly more likely to become infected
with what some researchers call the "superbug" MRSA â€“
methicillin-resistant Staphylococcus aureus
â€“ than are heterosexuals, according to a new study. Much of the
transmission appears to be through sexual contact, though historically,
transmission often is through non-sexual contact, generally via hands that
touch infected skin or non-living surfaces contaminated with the bacteria. [See
article, page 19].

The study, by researchers at the University of California,
San Francisco, was met with criticism by some activists and physicians, who
said that drug resistant staph has been around for years and that this latest
research provided little new information.

Binh An Diep, PhD, a researcher at UCSF and the lead author
of the study, said part of the reason why he conducted the study was to help
empower gay men to take better care of their own health. It was published
online in the Annals of Internal Medicine
on January 14.

However, Diep made several statements in a news release that
fanned the flames of homophobia. Anti-gay groups seized on the study, with one
calling gay men a "public health hazard."

Given the hysteria in much of the media coverage of the
recent studies on MRSA, Diep said that he is concerned there will be a possible
backlash against the gay community because of how his study might be presented
through the mainstream media. He made the comparison with the early days of the
HIV epidemic in this country. Back then, more than two decades ago, gay men
faced discrimination, and even as recently as 1992, current Republican
presidential candidate Mike Huckabee suggested that people living with AIDS be
"isolated" from the general population.

San Francisco physician William Owen told the Bay Area
Reporter Tuesday that he sees little new in
the latest study.

"I really don't think it's news," Owen said.

In a November 2007 article about drug resistant staph, Dr.
Erica Pan, an infectious disease
specialist in the San Francisco Department of Public Health's communicable
disease control and prevention section, told the B.A.R.
that people "should be
aware" of MRSA, but that calling it
a "superbug," as some have, is an overstatement.

The study

One part of the study retrospectively looked at the medical
charts of patients with confirmed MRSA for the period 2004 to June 2006 at
sites representing 98 percent of all hospital beds in San Francisco and two
public outpatient clinics. It randomly sampled 532 (21 percent) of the 2,495
cases for extensive review and the very time consuming analysis of the genetic
sequences of the MRSA bacteria samples.

The USA300 strain of MRSA is dominant in community
(non-healthcare) settings and often is more virulent in infecting young,
healthy persons. It is resistant to some antibiotics but it is still relatively
easy to treat. A subgroup of USA300 has acquired an additional genetic
sequence, pUSA03, that makes it resistant to a greater number of drugs and
hence more difficult to treat. It is known as multidrug-resistant (MDR) USA300.

Diep found the annual incidence of USA300 infection per
100,000 persons was 275 cases, while the incidence of the MDR variant was 26
cases in all of San Francisco. Geographically, eight contiguous Zip codes had
an average incidence of 59 cases, compared with four cases in the rest of the
city.

Overlaying that with census information, he found that
higher rates of infection with USA300 correlated with higher numbers of
self-reported male same-sex couples. In the first cluster of Zip codes, 10.3
percent of the population was male same-sex couples, compared with 2.2 percent
in the rest of the city.

The Castro District (Zip code 94114) had the highest
percentage (25.7 percent) of male same-sex couples in the United States, and a
MDR USA300 incidence rate per 100,000 of 170 cases. However, the total number
of cases in an individual Zip code is small and so the statistical confidence
interval is large; one should we wary of drawing too many conclusions from the
subset analysis.

SFGH HIV clinic study

An analysis of 183 consecutive patients with MRSA infection
treated at the San Francisco General Hospital HIV clinic found that most (179)
were skin or soft tissue infections. The vast majority (170) was caused by
USA300, and 30 of those were of the MDR variety. The latter group of infections
was more likely than other variants to be found on the buttocks, genitals, and
perineum â€“ the area between the anus and the scrotum â€“ than other
anatomical sites (30 percent versus 14 percent).

Diep said they saw little difference among HIV-positive
patients in terms of acquisition of MRSA, disease progression, or response to
therapy. However, most of those patients had a CD4 count greater than 200.
Significant risks of opportunistic infections often are not seen until the CD4
count drops below 100, and the number of patients in that category was too
small for meaningful analysis.

Boston study

Part of the study was conducted in Boston at Fenway
Community Health, a clinic that primarily serves the LGBT community. It was
drawn from data gathered as part of a larger, ongoing study. It involved 130
patients with MRSA; almost all (126) were infected with USA300, nearly half
(60) the MDR variant.

The Fenway study actively screened patients for colonization
with MRSA at four anatomic sites, something that is not done as part of normal
care for the infection. So it was no surprise that it identified a greater
presence of the bacteria on each patient.

The broader screening of all participants in that study, not
just those with active MRSA infection, found that 4 percent carried USA300 in
the nose and 2 percent in the perianal area â€“ around the anus and over to
the scrotum.

"This is an extremely high rate of perianal
colonization that is practically unheard of," Diep said.

Comparing the SFGH and Fenway groups, he found the risk for
MDR USA300 on the buttocks, genitals, or perineum was 30 percent and 47
percent, respectively. As those sites are where there is physical contact
during anal sex, it strongly suggests that transmission is occurring during
that activity.

The study also identified a Boston patient who regularly
traveled to San Francisco; his medical chart specifically mentioned the 94114
Zip code. Given the identical genetic sequences of the USA300 clones found in
both cities, it seems likely that they shared a common origin and were
disbursed by travelers from that site to other, perhaps many, locations.

Fenway's research director, Dr. Kenneth Mayer, said the
retrospective nature of the study made it impossible to ascertain the effect of
multiple sexual partners on risk of acquisition of MRSA or link that
acquisition to any particular venue or sexual activity.

He acknowledged that bathhouses and sex clubs, not to
mention gyms, are all possible locations for acquisition of MRSA through
contact with surfaces contaminated with the bacteria; sexual activity is not
required for transmission.

Issues of infection control are likely to become more
important in venues where sex occurs. Some cities, including San Francisco,
banned bathhouses in the early days of the AIDS epidemic in an attempt to
control transmission of the virus. Sex clubs often sprang up to take their
place. The main difference between the two is that the baths have shower
facilities and the clubs often do not. One exception in San Francisco is Club
Eros, which does have shower facilities, a spokesman said. Soap and water are
the cornerstone of controlling MRSA infection.

Taken together, these findings add to the growing body of
research showing that MRSA is a dynamic bacteria that is constantly evolving
into a more fit pathogen that is more readily adapted to transmission during
sexual contact and is more resistant to currently available antibiotics.